Studies were conducted on the host plants of four billbug species (Coleoptera:Curculionidae: Sphenophorus parvulus Gyllenhal, S. venatus Chitt., S. inaequalis Say, and S. minimus Hart) found on New Jersey turfgrasses. A collection of 4803 adults from pure stands of various turfgrasses revealed all four billbugs on Kentucky bluegrass (Poa pratensis L.), tall fescue (Festuca arundinacea Schreb.), and perennial ryegrass (Lolium perenne L.), and S. parvulus, S. venatus, and S. minimus on Chewings fescue (F. rubra L. ssp. commutata Gaud.). Since the presence of larvae, pupae, or teneral adults more accurately indicates the host status of a grass species, immature billbugs were collected from plugs of the various grass species and reared to adults for identification. All four species were reared from immature billbugs found in Kentucky bluegrass turf; immatures of S. venatus, S. inaequalis, and S. minimus were found in tall fescue; S. venatus and S. minimus in perennial ryegrass; and S. inaequalis in strong creeping red fescue (F. rubra L. ssp. rubra). A laboratory experiment was also conducted in which billbug adults were confined in petri dishes with either Kentucky bluegrass, perennial ryegrass, tall fescue, or bermudagrass (Cynodon dactylon Pers.). Only minor differences were found between the four grasses in billbug survival, number of eggs laid, and amount of feeding. In general, bermudagrass was the least favored host and the other grasses were equally adequate hosts. The results of this study indicate a need for updating host-plant lists of these four billbug species.
Optimizing Pre-germination Techniques for Kentucky Bluegrass and Perennial Ryegrass1
